I've been friends with someone for 20 years. We were single and fun-loving in our 20s, but over the past 10 years, as people have settled down, stopped partying so much, and concentrated on finding partners, she is not finding anyone and does nothing proactive to do so. She's a very nice and supportive friend at times, but also has periods when she gets angry and stops talking to us. She pokes a lot of fun at me under the guise of humor. I get very stressed about what I say to her, as I don't want to offend her. But if I'm working this hard to keep things afloat — maybe she's the one with the problem. Maybe I don't always do the perfect thing as a friend, but I try to be open. I think a lot of her behavior stems from loneliness, but she never just comes out and asks to talk about her fears or disappointments. I'm frustrated. What do I do?

Let me tell you something that Hallmark doesn't want you to know: Friends are like mutual funds. You don't give up on them as soon as they start to underperform, but if you're continually sinking resources into the relationship with no return on your investment, there's really no point in hanging on.

Bad reasons to end a friendship: She's single, lonely, and doesn't want to talk about her fears.

Good reasons to end a friendship: She's easily angered, subjects you to the silent treatment, and makes fun of you a lot.

Are you getting anything of value from this friendship? Does she make you feel good about yourself, or teach you something worthwhile, or understand you like no one else does?

Then again… are you giving anything of value? Do you show her that she's just as important to you now as she was in your 20s, and encourage her to share her disappointments with you?

If the friendship has run its course and it doesn't feel good anymore, it's OK to let it go. But if you still value it, then it doesn't matter if "she's the one with the problem"; in order to have a friend, you've got to be a friend.